Summary of Work: A research effort to identify mouse homologues of genes which cause hereditary hearing impairment is being initiated. Hearing deficient mutant mouse strains are excellent tools to identify genes that play crucial roles during development and functional organization of the mammalian inner ear. Of particular interest are the deaf waddler (dfw), Varitint-waddler (Va), ames waltzer (av), and jackson circler (jc) strains which selectively affect the sensory cells. Our goal is to positionally clone the deaf waddler gene, characterize the function of the gene product and to evaluate dfw as a candidate gene for DFNB6, which has been identified as a cause of nonsyndromic hereditary hearing impairment in several families .